BLS Healthcare Provider
Adult Cardiac Arrest Algorithm

As a healthcare provider, you need to be prepared to quickly and correctly help patients in the event of a cardiac arrest emergency. This algorithm shows the steps for both single rescuers and multiple rescuers of an unresponsive adult. Please enjoy our interactive algorithm. CLICK ON ANY BOUNCING OBJECTS AND LISTEN AS YOU FOLLOW ALONG, or simply click on the expand icon in the top right corner to see the whole algorithm.

BLS for Adults

Verify scene safety. If you encounter a potential cardiac arrest victim, first make sure the scene is safe for both the rescuers and the victim.

Check responsiveness. Get help. Check for responsiveness. First tap the victim and shout “HEY! HEY! Are you OK?” If they do not respond, shout for help. Activate the emergency response system. If you are alone, retrieve an AED and other emergency equipment. Send someone to get it if others are available.

Assess for breathing and pulse. Check for absent or abnormal breathing by watching the chest for movements for 5 to 10 seconds. Simultaneously check the carotid pulse for a minimum of 5 seconds—but no more than 10 seconds—to determine if there is a pulse present. It’s important to minimize delay in starting CPR, so take no more than 10 seconds to assess the patient.

If the victim has a pulse and is breathing normally, monitor them until emergency responders arrive.

If the victim has a pulse but is breathing abnormally, maintain the patient’s airway and begin rescue breathing. Administer one breath every 5 to 6 seconds, not exceeding 10 to 12 breaths per minute. Activate the emergency response system if you haven’t already done so. Check the patient’s pulse every 2 minutes. If at any point there is no pulse present, begin administering CPR. If you suspect a possible opioid overdose, administer naloxone if available and protocols allow.

Begin CPR. If a pulse is not identified within 10 seconds, immediately begin administering CPR, starting with chest compressions. Compressions should occur at a rate of 100 to 120 compressions per minute, with a depth of 2 inches. Use a compression-to-ventilation ratio of 30 compressions to 2 breaths.

Attempt defibrillation with the AED. The AED should be used as soon as it arrives or is ready. Follow the prompts on the AED to check for a shockable rhythm.

If the AED advises that the patient has a shockable rhythm, follow the prompts, clear the patient, and deliver the shock. Immediately resume CPR, starting with compressions, for 2 minutes or until the AED prompts you to check the patient’s rhythm again. Compressions should not be discontinued for more than 10 seconds. Continue providing CPR and following the AED prompts until ALS providers can take over or the victim begins to breathe, move, or react.

If the AED advises that the patient’s rhythm is nonshockable or no shock is advised, immediately resume CPR, starting with compressions. Continue CPR for 2 minutes, or until the AED prompts you to check the patient’s rhythm again. Compressions should not be discontinued for more than 10 seconds. Continue providing CPR and following the AED prompts until ALS providers can take over or the victim begins to breathe, move, or react.